Adjustable clamp for mounting elements on rotatable shafts



Oct. 12, 1954 D. DJKNOTT ADJUSTABLE CLAMP FOR MOUNTING ELEMENTS ON ROTATABLE SHAFTS Filed April 19. 1951 Patented Oct. 12, 1954 ADJUSTABLE CLAMP FOR MOUNTING ELEMENTS N ROTATAELE SHAFTS Donald D. Knott, Albuquerque, N. Mex., assignor to Allis-Chalmers Manufacturing Company,

Milwaukee, Wis.

Application April 19, 1951, Serial No. 221,871

4 Claims.

This invention relates in general to clamping members and in particular to members for adjustably clamping an element to a rotating shaft.

In electromagnetic contactors having a movable contact actuated by a rotatable shaft, the shaft is usually provided with a substantially polygonal cross section, and a clamping member comprising a pair of complementary clamping elements each engaging the shaft along the entire length of at least two sides of the shaft is secured to the contact to transmit the motion of the shaft to the contact. Such a clamping member has the disadvantage that the clamp cannot be rotated about the axis of the shaft to adjust the position of the clamp and contact relative to the shaft, since the clamping member engages the shaft along substantially the full length of at least four sides of the shaft and is therefore rigidly fixed relative thereto. This is especially disadvantageous where a plurality of contacts are mounted on one shaft and where, owing to mechanical diiference in the different contacts, it is necessary to adjust the contacts to produce alignment thereof radially of the shaft to insure simultaneous engagement with the fixed contact elements.

This disadvantage can be overcome by utilizing a clamping member which rigidly secures the movable element to the rotating shaft and which permits adjustment of the position of the element about the axis of the shaft.

It is therefore an object of this invention to provide an improved clamping device for adjustably securing a movable element to a rotating shaft.

It is an additional object of the present invention to provide means for clamping a movable element to a substantially polygonal rotatable shaft which permits adjustment of the position of the element about the axis of the shaft.

Objects and advantages other than those set forth above will be apparent from the following description when read in connection with the accompanying drawing, in which:

Fig. 1 is a partial end view of an electromagnetic contactor shown in partially open position utilizing the preferred embodiment of this invention;

Fig. 2 is a partial end view similar to Fig. l of the contactor adjusted to contact making position;

Fig. 3 is a side view of a portion of the electromagnetic contactor shown in Figs. 1 and 2; and

Fig. 4 illustrates an alternate embodiment of the clamping device of this invention.

Referring to Fig. 1, one embodiment of the invention is illustrated in connection with an electromagnetic contactor having a plurality of fixed contacts 5 secured to a suitable insulating base 6 by nuts 7 and studs ll. Each stud B may also be provided with a nut III to provide a terminal for connection to a circuit to be controlled by the contactor. A movable contact 9 is engageable with each contact 5 through movement imparted thereto by a shaft I2. Shaft I2 is journalled in brackets I3 secured to base 6 by bolts I l and is rotated about its axis by any suitable electromagnetic actuating means (not shown). Shaft l2 has any suitable substantially polygonal cross section, preferably the substantially rectangular cross section shown in Figs. 1 and 2, and is provided with an insulating coating l6.

Secured to shaft I2 is the clamping device of this invention comprising a first member 2| having a jaw portion 22 engaging shaft l2 and shank portions 23, 24 extending from the ends of jaw portion 22 and located on opposite sides of shaft I2. The clamping device further comprises a second member 25 having a jaw portion 26 engaging shaft l2 and shank portions 21, 28 on opposite sides of shaft I2. The jaw portion 26 of member 25 is shaped to engage shaft I2 at more than two points on-at least two sides of shaft i2, and preferably engages shaft I 2 along the entire surface of jaw portion 26, as shown in Figs. 1 and 2. Jaw portion 22 is shaped to engage shaft I2 at only two points on two sides of shaft l2, and preferably is provided with the arcuate surfaces shown in Figs. 1 and 2, engaging adjacent sides of shaft 12 at two points.

Suitable adjustable fastening means are provided to secure the clamp members to shaft i2, and such fastening means may comprise bolts iii, 32 extending through aligned openings in shank portions 23, 24, 27, 28. Bolts M, 32 extend loosely through the shank portions of one of members 2 I, 25, and as shown in Figs. 1 and 2, the bolts may extend loosely through the open ings in shank portions 21, 28 of member 25 and adjustably engage threaded portions of the openings in shank portions 23, 24.

Member 2| is provided with an extension forming a finger 34 bearing against a U-shaped conductive plate 35 secured to movable contact 53 by a bolt 36. A stud 31 extends with clearance through an aperture in the extension of member 2! and has a nut 38 secured to one end thereof. A flexible conductive lead til, representing a connection to the circuit to be controlled by the contactor, may be connected to plate 35 and movable contact 9 by studs aligned With stud ill and nuts aligned with nut 38. A spring 39 compressed between a nut 4E and finger 34 pulls against member 35 and causes member '35 and contact 9 to pivot about finger 34 when contact 9 engages contact 5, to provide a wiping engagement and disengagement of contacts 5, 9. Member 21 is thus connected to contact 9 and imparts movement of shaft 12 to contact 9.

To vary the position of movable contact 9 about the axis of shaft l2, the adjustable fastening means are adjusted to rotate member 2! about shaft [2. In Fig. 1, representing one adjustment of the clamping device, the distance A between the inner ends of adjacent shank portions 23, 21 is equal to the distance B between the inner ends of adjacent shank portions 24, 28, and contact 9 assumes the position shown. If it is desired to move contact 9 closer to contact without rotating shaft !2, bolt 32 is advanced in the threaded opening in shank portion 24 and bolt 3! is withdrawn in the threaded opening in shank portion 23. This action causes member 2! and contact 9 to rotate counterclockwise about shaft 12 on the two pivot points provided by the engagement of the jaw portion 22 with the two sides of shaft [2.

As shown in Fig. 2, this movement reduces the distance B between shank portions 24, 2S and increases the distance A between shank portions 23, 21, and causes contact 9 to approach contact 5. During the above described adjustment, the position of member 25 relative to shaft 12 is fixed owing to the engagement of jaw portion 26 with shaft [2 along the entire surface of portion 28. Adjustment of bolts 3!, 32 in the direction opposite to that described above will cause member 2| and contact 9 to rotate clockwise about shaft l2, and the amount of movement of contact 9 may be accurately controlled by bolts 3|, 32.

The clamping device of this invention is especially useful where a plurality of elements are actuated by a common rotatable shaft, as shown in Fig. 3, where several movable contacts 2 are actuated by the common rotatable shaft 112. In such contactors, it is desirable that all of the movable contacts engage and disengage their respective fixed contacts simultaneously to insure proper division of current between the different contact sets. Since mechanical differences in the component parts of such a contactor make it unlikely that such simultaneous engagement and disengagement would occur without adjustment, some adjustment of the position of contacts 9 relative to shaft I2 is required. This adjustment is provided by utilizing the clamping device of this invention, as described above, so that the plurality of contacts 9 may be aligned radially of shaft l2 to produce the desired result.

Fig. 4 illustrates an alternate embodiment of the invention in which a hexagonal actuating shaft I2 is provided, having an insulating coating l6 thereon. In this embodiment, the clamp member 25 has a jaw portion 26 preferably engaging shaft |2 on three sides thereof along the entire surface of jaw portion 26 to rigidly secure member 25 relative to shaft l2. Jaw portion 22 of member 21 engages two sides of shaft l2 at only two points thereon, so that member 2] is free to rotate about shaft [2. Shank portions 23, 24 are provided with built-up sections or blocks as having threaded continuations of the threaded openings in shank portions 23', 24.

Bolts 3!, 32 extend loosely through shank portions 21, 28, respectively, and adjustably engage the openings in shank portions 23, 24, respectively. It will be noted that bolts 31, 32 do not extend entirely through shank portions 23, 24, as in the other embodiment, owing to blocks 46. The embodiment of Fig. 4 operates substantially as described above in connection with the other embodiment, to produce rotation of member 21 about shaft [2 upon adjustment of bolts 3!, 32.

Although but two embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims. In particular, although the clamping device of this invention has been illustrated in connection with an electromagnetic contactor, it will be apparent that the device may be utilized in many other applications,

It is claimed and desired to secure by Letters Patent:

1. In a device having an element to be moved and a shaft for moving said element, said shaft having a plurality of flat sides and having a substantially polygonal cross section, a clamp for adjustablv securing said element to said shaft in adjustable angular relation thereto, said clamp comprising a first member connected to said element and a second member, said first member having a first jaw portion spaced from the edges of said shaft and having two arcuate portions engaging said shaft at only two variable points on two of said sides and first and second shank portions extending from the ends of said jaw portion, said second member having a second jaw portion shaped to engage said shaft at more than two points around the periphery of said shaft and third and fourth shank portions extending from the ends of said second jaw portion, and adjustable means for varying said two points of engagement of said first jaw portion with said shaft to rotate said first member and said e1ement with respect to said shaft, said adjustable means comprising first adjustable fastening means secured to said first and third shank portions and second adjustable fastening means secured to said second and fourth shank portions.

2. In combination, an element to be moved, a rotatable shaft having a plurality of flat sides and having a substantially polygonal cross section for moving said element, and a clamp for adjustably securing said element to said shaft in adjustable angular relation thereto comprising a first member connected to said element and a second member, said first member having a first jaw portion spaced from the edges of said shaft and having two arcuate portions shaped to engage said shaft at only two variable points on two of said sides and first and second shank portions extending from the ends of said jaw portion, said second member having a second jaw portion shaped to engage said shaft along substantially the entire surface of said second jaw portion and third and fourth shank portions extending from the ends of said second jaw portion, and adjustable means for varying said two points of engagement of said first jaw portion with said shaft to rotate said first member and said element with respect to said shaft, said adjustable means comprising parts of the shank portions of one of said members provided with a pair of openings and a pair of bolts extending loosely through said openings and adjustably engaged with the shank portions of the other of said members.

3. In combination, an element to be moved, a rotatable shaft having a substantially hexagonal cross section for moving said element, and a clamp for adjustably securing said element to said shaft in adjustable angular relation thereto comprising a first member connected to said element and a second member, said first member having a first jaw portion spaced from the edges of said shaft and having two arcuate portions shaped to engage said shaft at only two variable points on two sides of said shaft and first and second shank portions extending from the ends of said jaw portion, said second member having a second jaw portion shaped to engage said shaft at more than two points on at least two of said sides of said shaft and third and fourth shank portions extending from the ends of said second jaw portion, and adjustable means for varying said two points of engagement of said first jaw portion with said shaft to rotate said first member and said element with respect to said shaft, said adjustable means comprising parts of the shank portions of one of said members provided with a pair of openings and a pair of bolts extending loosely through said openings and adjustably engaged with the shank portions-of the other of said members.

4. In combination, an element to be moved, a rotatable shaft having a plurality of flat sides and being of substantially rectangular cross section for moving said element, and a clamp for adjustably securing said element to said shaft in adjustable angular relation thereto comprising a first member connected to said element and a second member, said first member having a first jaw portion spaced from the edges of said shaft and having two arcuate portions shaped to engage said shaft at only two variable points on two sides of said shaft and first and second shank portions extending from the ends of said jaw portion, said second member having a second jaw portion shaped to engage said shaft at more than two points on at least two of said sides of said shaft and third and fourth shank portions extending from the ends of said second jaw portions, and adjustable means for varying said two points of engagement of said first jaw portion with said shaft to rotate said first member and said element with respect to said shaft, said adjustable means comprising parts of said third and fourth shank portions provided with a pair of openings and a pair of bolts extending loosely through said openings and adjustably engaged with said first and second shank portions.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 360,645 Baute Apr. 5, 1887 403,902 Bailey May 28, 1889 409,878 Smith Aug. 27, 1889 953,658 Brockett Mar. 29, 1910 959,475 Davis May 31, 1910 1,568,101 Taylor Jan. 5, 1926 1,747,320 Rea Feb. 18, 1930 1,905,784 Alasker Apr. 25, 1943 2,547,932 Downs Apr. 10, 1951 FOREIGN PATENTS Number Country Date 18,597 Great Britain of 1893 

